Digital voice communications have been performed over circuit-switched networks. A circuit-switched network is a network in which a physical path is established between two terminals for the duration of a call. In circuit-switched applications, a transmitting terminal sends a sequence of packets containing voice information over the physical path to the receiving terminal. The receiving terminal uses the voice information contained in the packets to synthesize speech.
Digital voice communications have started to be performed over packet-switched networks. A packet-switch network is a network in which the packets are routed through the network based on a destination address. With packet-switched communications, routers determine a path for each packet individually, sending it down any available path to reach its destination. As a result, the packets do not arrive at the receiving terminal at the same time or in the same order. A de-jitter buffer may be used in the receiving terminal to put the packets back in order and play them out in a continuous sequential fashion.
On some occasions, a packet is lost in transit from the transmitting terminal to the receiving terminal. A lost packet may degrade the quality of the synthesized speech. As such, benefits may be realized by providing systems and method for preventing the loss of information within a speech frame.